Project V will evaluate HIV vector-mediated delivery of anti-HIV ribozyme genes into stem cells, followed by autologous stem cell transplantation (ASCT) for the treatment of AIDS lymphoma. This project will specifically address the issue of safety in HIV-vector application using novel methods for vector modification and production. In addition, improved assays for detecting helper-virus contamination in vector preparations will be established. For gene therapy-based ASCT in AIDS lymphoma patients, this project will develop anti-HIV-1 ribozymes designed for use not only for the improvement of safe vector production, but also for eventual anti-viral effect in the clinical study. The study of the HIV vector and the efficacy of the anti-HIV ribozymes delivered by the vector will be evaluated in transduced CD34+ cells derived from AIDS lymphoma patients in preclinical studies. Finally, a clinical trial of HIV-vector transduced ASCT will be completed in a study of AIDS- related non-Hodgkin's lymphoma and Hodgkin's disease. Methods for the production of helper free HIV vectors will utilize ribozymes that target HIV sequences that are not included in the vector and sequences of VSV-G that are crucial to vector packaging. The candidate HIV-vector chosen for clinical trial will have been exhaustively analyzed for absence of helper virus. In addition to protection of the production lot from contamination with helper virus, this vector will also encode anti-HIV ribozymes that could potentially have activities in vivo against HIV-1 infection and influence long-term survival This project will advance the theme of the Program by seeking to improve the outcome of transplantation for hematologic malignancy. In addition, interactions of Project II, Project IV, and Project V, in which HIV-vectors and AAV- vectors are evaluated for stem cell gene delivery, will permit a comparison of these vectors within a similar patients groups for transduction efficiency, cell engraftment, and duration of transgene expression.